[Boatanchors] MR-1 Comanche

[NE7X@aol.com]

I am restoring a Heathkit MR-1 Comanche receiver. It looks
like I have just about every bug/issue resolved except one.
The BFO pulls the product detector on strong signals,
resulting in BFO freq shift.

I had the same problem with my Apache RX-1 receiver and 
resolved this issue by putting in the K6AD BFO and product
detector mod described in Electric Radio. This mod separates
the BFO from the product detector using a N-channel MOSFET
for the BFO.

The MR-1 and RX-1 use the exact same design, so I am assuming
the K6AD BFO and product detector mod should work in the MR-1.
However, the RX-1 product detector is at 50 kc and the the
MR-1 product detector is at 3MC. So to use a direct circuit
replacement will most likely not work.

Has anyone placed a K6AD or equivalent mod in the MR-1
BFO / Product Detector circuit to stabilize the BFO from
pulling? If so, I would like to hear from you on lessons learned.

73s, Tom NE7X...
http://www.ne7x.com